In this paper, a novel wideband single-feed circularly polarized patch antenna is presented. The antenna consists of an L-shaped probe, four parasitic patches perpendicular to the probe, and a planar reflector. By modifying the structure of the patches, two orthogonal radiation modes are created to realize the circular polarization in the broadside direction. This antenna exhibits a wide impeda...

Abstract—A novel circularly polarized cavity-backed antenna (CBA) excited by crossed bowtie dipoles is presented in this paper. It is fed by a transition from a microstrip line to doubleslot lines. The crossed dipoles consist of a top-loaded triangular and a filleted rhombic to achieve the required input impedance relations for circularly polarized radiation. After optimization, a simulated 3-d...

A frequency tunable ring dielectric resonator antenna is presented in the paper. Advantages of the proposed antenna design are the wide range of adjustments and increasing of the radiation efficiency. The basic antenna characteristics, and also analysis of dependencies of the antenna’s central operating frequency, voltage standing wave ratio and radiation pattern versus the relative position of...

To perform a non-destructive evaluation of wood, the Christoffel equation is frequently used to describe the relationship between the ultrasonic wave velocity and the mechanical parameters. In the context of acoustical tomography imaging of standing trees, the key contribution of this numerical study is to determine the influence of mechanical parameters of the wood radial-tangential plane on t...

local site conditions have a strong effect on ground response during earthquakes. two important soil parameters that control the amplification effects of seismic motions by a soil column are the soil hysteretic damping ratio and shear wave velocity. this paper presents the results of in situ damping ratio measurements performed using continuous surface wave attenuation data at a site in semnan ...

X-ray diffraction from crystal surfaces at grazing angles gives rise to X-ray standing waves above and below the surface. Expressions are derived for the fluorescence observed from atoms located on or in a crystal as a result of excitation by the grazing-angle X-ray standing waves. In addition to the dependence of the fluorescence on the position of the atom with regard to the crystal plane tha...

A fluorescence correlation spectroscopy experiment that combines two-photon excitation and a standing-wave interference pattern is presented. The experimental correlation function can be analyzed using a simple expression involving (1) an exponential decay with time constant tau(f), which reflects diffusion across the interference fringes, and (2) a longer-lived decay with time constant tau(ome...

The clock signal of modern computer processors consumes a large portion of overall chip power. By modeling global clock network wires as transmission lines and manipulating their dimensions, the global clock signal can be transformed into a standing-wave oscillator that conserves energy and reduces skew. This paper explains the lossy transmission line model and explores the effects of matching ...

Introduction The X-ray standing wave (XSW) technique provides an element-specific structural probe by using x-ray reflectivity to generate a " two-beam " interference field that in turn induces a spatial dependence to the x-ray spectroscopic yields from atoms within the field. The XSW technique is primarily used for resolving the atomic-scale structure at surfaces, interfaces, and thin films wi...